Historically, farmers in all areas of the world have used irrigation to increase the number and types of crops that can be grown. Irrigation has allowed arid, unproductive land to be turned into fertile farm land. Flood irrigation was the original type of irrigation. To irrigate by flood, a river or stream was diverted from its natural bed and into the farm ground. More recently farmers have become conscious of the cost and scarcity of water. Because of water scarcity sprinkler irrigation has become a popular type of irrigation.
In early sprinkler irrigation systems the individual pipes had to be moved manually. Now, because of labor costs and other difficulties associated with moving pipes, automated irrigation is rapidly becoming the favored form of sprinkler irrigation.
One widely used automated irrigation system is commonly known as a “pivot” or “pivot sprinkler system.” A pivot sprinkler system has a main arm extending outward from a center pivot structure. The main arm generally comprises a series of pipe sections, that transport water. The pipe sections hold sprinkler heads configured to deliver the water to the field. Each pipe section of the main arm is supported by a tower. The towers are generally supported by two powered wheels. As these wheels turn, the main arm rotates about a central pivot structure. Water is supplied to a fixed inner end of a pipe section and distributed to the sprinklers placed along the pipeline. As the main pipeline section moves about its central pivot structure it irrigates a circular portion of the field.
These automated irrigation systems move in a circular pattern, and because of this, the corners of square fields are not watered by the irrigation system.
To address this short coming, automated irrigation systems have been recently fitted with a steerable swing arm. The irrigation systems are guided by a computerized system that can determine the location of the irrigation system in the field. When the computer determines that the main pipe section of the automated irrigation system is approaching a corner, the steerable swing arm swings out into the corner of the field and irrigates the corner. This guidance is assisted typically by guidewires or markers buried in field that inform the computer of the position of the pivot system in the field.
While this swing arm is effective for watering in square corners, the swing arm is ineffective in many aspects. These swing arms have a corner tower that is supported by two shafts each riding on a single wheel. This configuration places considerable pressure on the wheel, which usually results in deep ruts in muddy, irrigated fields. As the pivot irrigation system moves over the field during a growing season, these ruts may grow deeper and deeper. As the ruts grow deeper the wheels are more prone to becoming stuck. Others have attempted to remedy this problem by using a larger wheel so that the ground pressure from the tower is lightened, but tires for these large wheels are scarce and therefore installation and replacement are expensive. Moreover, the width of a single tire is of little importance if that single tire has become stuck.
When the wheels of the swing arm become stuck, the rest of the irrigation system, nonetheless, may continue across the field causing the irrigation system to bend, break, or tip over. Even if the stuck wheel is discovered, or the pivot system shut of, before the system is damaged, it can be difficult to remove a pivot wheel that has become stuck. Such removal often requires many man-hours and heavy or specialized equipment. This equipment moreover can crush or damage crops or the irrigation system. Frequently, it is necessary to allow the field to dry before attempting to remove a stuck wheel. During certain times of the year crops are very susceptible to drought and may be damaged while allowing the field to dry sufficiently. This damage may result in a reduced, or non-existent crop yield.
An additional problem with current systems is that considerable force and torque can be applied to the support wheel of the swing arm by the weight of the water pipes. This torque can cause the axle or drive shaft that supports the wheel to bend or break. Such damage to the swing arm will be costly to repair and may result in significant down time.
Accordingly, it would be an advantage to provide a swing arm support system that would minimize the depth of ruts formed in a field. It would be an additional advantage if the support system was less susceptible to bending or breakage. It would be an additional advantage to provide a solution that could be retrofitted to current corner swing arm support towers. It would be an additional advantage to use commonly produced parts that could be used interchangeably with other parts commonly used in irrigation systems.